The use of organic phosphors is advantageous in relation to inorganic phosphors, e.g. with regard to designing the position and bandwidth of the luminescence spectrum thereof. Unfortunately, organic phosphors have turned out to be sensitive to ambient substances, such as oxygen and water, which prematurely degrades the phosphor. Efforts have been made to solve this problem. U.S. Pat. No. 7,560,820 discloses a light emitting diode (LED) comprising a closed structure which encloses a cavity with a controlled atmosphere. In the cavity there are arranged an emitter element, phosphor arranged close to the emitter element, and a getter. It is desirable to obtain a similar larger scale structure with one or more LEDs.